Cannot upload blob using docker

I have succeeded to deploy my app, but I am stuck using the blobstore. I am using docker and started it with -p 8888:8080. I can access my application via {ip-of-machine}:8888/index.html

When I try to upload a blob the following happens: I call the BlobStoreService to create an upload url with a redirect to "/rest/application/blob". The file seems to get uploaded but I get the following error message: There was an error with your upload. Redirect path not found. Please contact the app owner if this persists.</br>Server: nginx/1.4.6 (Ubuntu)